Move runtime files to C instead of C++

Explicitly have the only C++ portion of the runtime be one file with exception
handling. All other runtime files must now live in C and be fully defined in C.

src/rt/rust_android_dummy.cpp

@@ -1,107 +0,0 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifdef __ANDROID__
-
-#include "rust_android_dummy.h"
-#include <math.h>
-#include <errno.h>
-
-int backtrace(void **array, int size) { return 0; }
-
-char **backtrace_symbols(void *const *array, int size) { return 0; }
-
-void backtrace_symbols_fd (void *const *array, int size, int fd) {}
-
-extern "C" volatile int* __errno_location() {
-    return &errno;
-}
-
-extern "C" float log2f(float f)
-{
-    return logf( f ) / logf( 2 );
-}
-
-extern "C" double log2( double n )
-{
-    return log( n ) / log( 2 );
-}
-
-extern "C" void telldir()
-{
-}
-
-extern "C" void seekdir()
-{
-}
-
-extern "C" void mkfifo()
-{
-}
-
-extern "C" void abs()
-{
-}
-
-extern "C" void labs()
-{
-}
-
-extern "C" void rand()
-{
-}
-
-extern "C" void srand()
-{
-}
-
-extern "C" void atof()
-{
-}
-
-extern "C" int glob(const char *pattern,
-                    int flags,
-                    int (*errfunc) (const char *epath, int eerrno),
-                    glob_t *pglob)
-{
-    return 0;
-}
-
-extern "C" void globfree(glob_t *pglob)
-{
-}
-
-extern "C" int pthread_atfork(void (*prefork)(void),
-                              void (*postfork_parent)(void),
-                              void (*postfork_child)(void))
-{
-    return 0;
-}
-
-extern "C" int mlockall(int flags)
-{
-    return 0;
-}
-
-extern "C" int munlockall(void)
-{
-    return 0;
-}
-
-extern "C" int shm_open(const char *name, int oflag, mode_t mode)
-{
-    return 0;
-}
-
-extern "C" int shm_unlink(const char *name)
-{
-    return 0;
-}
-
-extern "C" int posix_madvise(void *addr, size_t len, int advice)
-{
-    return 0;
-}
-
-#endif